Samsung Electronics Co. Ltd., which has urged users of its Galaxy Note 7 smartphone to turn them in due to fire-prone batteries, said it will perform a software update in South Korea that limits the devices' charge to 60 percent.

The move comes as Samsung, the world's biggest smartphone maker, also ran local advertisements apologizing for a recall that is unprecedented for a company that prides itself on its manufacturing prowess.

It has not decided whether to implement similar software upgrades limiting battery charging in markets other than South Korea, a company spokeswoman said.

The software update, which will be automatic, will begin at 2 a.m. local time on Sept. 20, Samsung said in a statement.

The firm has sold 2.5 million Note 7 phones in 10 markets including South Korea and the United States that are subject to the recall.

Samsung plans to begin offering replacement phones with safe batteries on Sept. 19 in South Korea.

A series of warnings from regulators and airlines around the world has raised fears for the future of the flagship device, pushing Samsung shares lower.

South Korea's markets were closed on Wednesday for a public holiday.

($1 = 1,124.7700 won)

(Reporting by Tony Munroe and Se Young Lee; Editing by Edwina Gibbs)

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